Blue tooth phone to carputer question

I have decided to get a cell phone with blue tooth and add it to my carputer. I am only interested, at the moment, to make and receive calls with the sound coming through the speakers. I just want to make sure I have everything straight. I would need a cell with blue tooth technology, Blue tooth USB Adapter, microphone, and my car speakers. I am running xp pro and RR as my front end. Am I forgetting anything?